Mechanical pencil for fine leads

ABSTRACT

A mechanical pencil for fine leads with a pushbutton-type lead advancing mechanism, a conical ferrule at the writing end of the barrel and a plug connecting the ferrule to the barrel. The plug is so arranged that it reaches deep into the ferrule, thereby rendering the writing end of the barrel more rigid and shortening the distance between the pencil tip and the clutch head which advances the lead.

United States Patent l lo? a 92 [56] References Cited UNITED STATESPATENTS 2,222,295 1 1/1940 Kanner 401/65 2,473,149 6/1949 .luelss 401/652,627,842 2/1953 Russell 401/65 Primary Examiner- Lawrence CharlesAttorney0tto John Munz ABSTRACT: A mechanical pencil for fine leads witha pushbutton-type lead advancing mechanism, a conical ferrule at thewriting end of the barrel and a plug connecting the ferrule to thebarrel. The plug is so arranged that it reaches deep into the ferrule,thereby rendering the writing end of the barrel more rigid andshortening the distance between the pencil tip and the clutch head whichadvances the lead.

PATENIED DEC! 4197! INVENTOR YUK IO HOR 11') BY a? z I ATTORNEYMECHANICAL PENCIL FOR FINE LEADS BACKGROUND OF THE INVENTION 1. Field ofthe Invention The present invention relates to mechanical pencils, andmore particularly to mechanical pencils having a pushbuttontype leadadvancing mechanism using a clutch to advance the lead by apredetennined increment, when a plunger button projecting from the rearof the pencil is depressed.

2. Description of the Prior Art A known mechanical pencil of the typementioned above uses a hollow cylindrical plug with a single thread onits outer surface to connect the ferrule to the pencil barrel. The plugis screwed into the front end of the pencil barrel by approximatelyone-half of its length, and with its other half it is screwed into therear end of the ferrule. The plug has an enlarged bore at the ferruleside and a smaller bore at the barrel side, with a shoulder betweenthem. Within the larger bore is arranged a clutch ring which is slidablymovable between the plug shoulder and an abutment shoulder in theferrule. Arranged inside this clutch ring is a clutch head which holdsthe lead in place. The ferrule includes in its center bore, near thewriting tip, a resilient gasket to frictionally hold the lead, therebypreventing the latter from falling out of the pencil when the clutchhead is opened. It serves the additional purpose of preventing the lead,once advanced, from moving back into the barrel with the returningclutch head.

The above design, where the clutch head is located in the region of therear end of the ferrule, has the shortcoming that a considerable lengthof lead remains unusable because of the great distance between theferrule tip and the clutch head. Furthermore, there exists thepossibility of the lead breaking, when a lateral force or shock isapplied to the tip of the ferrule thereby moving the axis of the ferruletip and guide sleeve out of alignment with the axis of the clutch head.This disadvantage becomes more important when very fine leads are used.For certain drafting applications, leads as thin as 0.012 inch (0.3millimeters) are being used nowadays. The addition of a lead guide tubein the tip of the ferrule for the protection of such fine leads furtherincreases the unusable length of lead.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a mechanical pencil with a pushbutton-type lead advancingmechanism, where the possible misalignment between the ferrule tip andthe clutch head under a lateral force to the ferrule tip is kept to aminimum, to prevent accidental breaking of the lead.

Another object of the invention is to provide a mechanical pencil of thetype mentioned, where the clutch head is located deep inside the taperedferrule and at a close distance from the writing tip, so as to minimizethe unusable length of lead, as determined by this distance.

Other objectives and advantages of the invention will become apparentfrom the detailed description of the invention, taken in conjunctionwith the accompanying drawings.

DRAWINGS FIG. 1 illustrates, at an enlarged scale, an embodiment of theinvention with portions thereof shown in a center cross section, andwith the center portion broken away;

FIG. 2 shows, at a further enlarged scale, the front portion of theembodiment of FIG. 1 in a center cross section:

FIG. 3 shows, at a scale comparable to that of FIG. 2, the front portionof a known mechanical pencil.

DETAILED DESCRIPTION AND OPERATION The mechanical pencil of FIGS. 1 and2 has a slender barrel 2 preferably molded of synthetic resin, a taperedferrule 3 in the front of the barrel, and an end cap 16 screwed to therear end thereof. To the barrel is fixedly attached a clip 1 l.

In the front portion of the pencil is arranged a plug 1 which iscomposed of three cylindrical sections: the plug section la, extendingto the rear of the plug 1, has a comparatively large outer diameterprovided with a screw thread thereon; the plug section 1b locatedforward of the plug section In has a comparatively small outer diameterequally provided with a screw thread; and the plug section Ic extendingto the front of the plug 1 has a still smaller diameter.

The barrel 2 has in the front portion of its bore an interior thread toreceive the plug section la. The tapered ferrule has a bore with athreaded rear section to receive the plug section lb, and forward ofthis threaded bore section a smaller cylindrical bore section tightlyfitting the plug section 10. When assembled as shown in FIG. 2, the plug1 firmly holds the ferrule 3 to the barrel 2.

The plug 1 has a central bore and, in its front portion, inside plugsection 10, an enlarged bore section with a rearward shoulder. Withinthis enlarged bore section is slidably arranged a clutch sleeve 4. Thefront end of the plug section 1c contacts an abutment shoulder in thebore of ferrule 3. This shoulder also limits the forward displacement ofthe clutch sleeve 4, while the rearward displacement of the latter islimited by the shoulder in the plug bore.

A lead guide 12, preferably of fine stainless steel tubing, is fixedlyattached to the front end of the ferrule 3 and accurately aligned withthe axis of the ferrule bore. The plug 1, by reaching deep into theferrule 3 with its plug section 1c, renders the front portion of thepencil more rigid, thereby preventing misalignment between the leadguide I2 and the clutch sleeve 4, when the ferrule is subjected tolateral forces or shock. Behind the lead guide 12 is arranged aresilient gasket 5 whose purpose it is to prevent the lead from slidingfreely into or out of the pencil.

Inside the pencil is arranged a longitudinally movable plunger assemblywhich operates in a known manner to hold and advance a lead through thelead guide 12. The plunger assembly consists of a plunger 7 reachingthrough the bore of the plug 1, a plunger casing 9 connected thereto bya plunger coupling 8 and extending through the barrel 2 into the end cap16, and a plunger button 14 detachably connected to the rear end of theplunger casing 9 and extending beyond the hollow end cap 16.

The plunger 7 is slidably guided inside the plug 1 and extends adistance into the barrel 2. The plunger coupling 8 is screwed to therear end of the plunger 7 and thereby retains a compression spring 10between it and the rear face of the plug 1. The plunger 7 carries on itsforward end a clutch head 6. This clutch head has a long thin neck of asmaller diameter than the head portion itself and, like a conventionalcollet, is slotted longitudinally to fonn several jaws, preferablythree.

The clutch head 6 is screwed into the plunger 7 by means of a threadprovided at its rear end, after the plunger assembly 7-8-9, the spring10, the plug 1, and the sleeve 4 have been preassembled. The clutchsleeve 4 has a central bore to accommodate the clutch head 6 therein,with a smaller diameter in its rear half, a larger diameter in its fronthalf, and a tapered interior shoulder therebetween. The plunger assemblyis pulled to the rear by virtue of the spring 10, causing the clutchhead 6 to be pulled into the sleeve 4 and against the tapered interiorshoulder, thereby closing the clutch jaws around a lead which reachesthrough the plunger 7 and the lead guide 12.

The plunger casing 9, preferably of thin metal tubing, is fixedlyattached on its front end to the plunger coupling 8. The coupling 8 hasa peripheral groove into which a wall portion of the casing 9 ispressed. Inside the plunger casing 9 may be stored a number of spareleads.

The plunger button, preferably molded of synthetic resin, has a neckportion removably insertable into the rear end of the plunger casing 9,a shoulder limiting the depth of insertion, and, radially projectingfrom this shoulder, a nose l3 fitting into a longitudinal groove 17 ofthe end cap 16. In the front end of the button 14 is arranged a thin pin15 of a diameter which is slightly smaller than the bore of the leadguide 12 and which reaches into the plunger casing 9. After removal fromthe casing, the plunger button can thus be used to clear the ferrule tipof fractured lead sections which may have been retained by the gasket 5.The plunger button can be removed by unscrewing the end cap 16.

in operation, the plunger button is depressed to advance the leadthrough the clutch head 6 and lead guide 12, by pushing the plungerassembly 7, 8, 9, l4 forward against the spring force of the compressionspring 10. This causes the clutch sleeve 4, which is in frictionalengagement with the clutch head 6, to be displaced forward until itsmovement is stopped by the abutment shoulder of the ferrule 3. Theplunger 7, and clutch head 6 clamping the lead, advance further throughthe plug 1 and sleeve 4 until the clutch head leaves the clutch sleeve4, thereby opening its jaws and releasing the lead. The lead, havingbeen advanced by a set increment, is now only held longitudinally by thegasket 5.

Release of the plunger button 14 allows the spring 10 to return theplunger assembly into its rest position while the lead remains in theforward position. The clutch head 6, while reentering the clutch sleeve4, moves the latter to its rear abutment position and upon contactingthe tapered shoulder inside the clutch sleeve 4, closes its jaws aroundthe lead, firmly gripping the latter. The nose 13 of the plunger button14, guided in the groove 17 of the end cap 16, prevents rotation of theplunger assembly. Such rotation could cause a.very fine lead to twistand break.

In FIG 3, is illustrated the front portion of a known mechanical pencilwith a pushbutton-type lead advancing mechanism. The reference numerals1', 2, 3', etc. of this figure refer to parts perfonning the same or asimilar function as the parts, 1, 2, 3, etc. of FIGS. 1 and 2.

A comparison between FIG. 2 and FIG. 3 shows that the plug 1 of theinvention has three successively smaller sections la, 1b and 1c, unlikethe plug 1' of the prior art, and that this permits arrangement of theclutch head 6 much closer behind the writing tip of the ferrule 3. Evenin the case where it is desirable to have a relatively long-taperedferrule 3 conforming to a gradually reducing profile of the barrel 2,the plug of the invention pennits a rigid connection between it and theferrule 3. Furthermore, the short-gripping distance between the clutchhead 6 and the gasket provides better protection of the lead, should theconnection between the plug section la and the barrel 2 deform underlateral forces or shock. The

remaining unusable length of lead, as determined by the distance betweenthe writing tip of the lead guide 12 and the front end of the clutchhead 6 is thereby kept to a minimum.

1 claim:

1. A mechanical pencil for fine lead having a pushbuttontype leadadvancing mechanism, comprising in combination:

An elongated barrel having a bore, a front end and rear end;

said barrel including an interior thread in said front end and an outerexternal diametrical alignment projection on said front end and an upperinternal thread and an internal diametrical alignment portion at saidrear end;

a rear end cap I, mounted on the rear end of said barrel having a bore,a front end with an external thread and an external diametricalalignment portion;

said external thread and said external alignment portion of said borebeing in diametrical alignment and fitting engagement with said upperinternal thread, and said internal diametrical alignment portion of saidrear end of said barrel;

a tubular plunger casing, with an upper end and a lower end, having thinmetal walls being a spare pencil lead magazine;

a plunger button of cylindrical shape having a necked portionnonrotatingly, slidably and reciprocatingly mounted in said end cap, thesaid upper end of the said plunger casing being removably mounted withits inside diameter upon said necked portion of said plunger button;

a sleevelike plunger coupling having an internal thread, an externaldiameter, an external circular groove and a necked diametrical part,said lower end of said plunger casing being fixedly mounted upon saidexternal diameter of said plunger coupling pressingly engaging saidcircular groove of said coupling;

a femile having an outside cylindrical rear portion and a forwardtapered portion, an internal diametrical fitting portion at said rearportion engaging fittingly said external diametrical fitting portion onsaid front end of said barrel;

said ferrule also having, starting in sequence at its said forwardportion, concentric cylindrical bores, comprising:

a first small bore.

a second oval-shaped bore,

a third bore,

a fourth bore,

an abutment between said third and said fourth bore;

a fifth bore, and

a sixth bore being an internal thread;

a plug rigidly connecting said barrel and said ferrule; said plug havingrear and front parts integrally arranged from its rear to front, saidrear part having:

a necked projection,

a larger external thread in fixed engagement with said interior threadin said front end of said barrel,

a relief diameter,

said front part having:

a smaller external thread in fixed engagement with said sixth bore beingan internal thread of said ferrule, and

a smaller outside diameter at said front part of said plugengagedaligningly and fittingly with said fourth bore of said ferrule,

said plug further comprising:

a long smaller bore starting at said rear part of said plug,

a conical bore, and a larger bore at its front part,

a tubelike plunger, having an upper part and a lower part,

said upper part comprising an external thread fixedly engaged with saidinternal thread of said plunger coupling and an outside diameter,fittingly and slidingly engaging in said long smaller bore of said plug,

said lower part of said plunger having a small internal thread at saidlower part, and comprising an inner bore of a size permitting passingsaid pencil lead therethrough;

a clutch head having a front end and rear end being concentric,comprising:

a long thin neck;

an external thread at said rear end fixedly mounted and in engagementwith said small internal thread at said lower part of said plunger;

an axial bore for slidingly passing and holding said pencil lead;

a colletlike clutch portion at said front end of said clutch head foralternately holding, feeding and clamping said pencil lead, said clutchhead having at least two longitudinal slots in said front end portionand being located in said forward portion of said ferrule,

whereby a larger portion of said pencil lead can be used a clutch sleeveslidably mounted in said larger bore in said front part of said plug,said clutch sleeve having an upper smaller bore and a lower larger boreand a conical clutch-affecting middle portion;

a compression spring axially mounted between said plunger coupling andsaid plug being held concentric by said necked diametrical part of saidcoupling and said necked projection of said plug;

a pencil lead-supporting gasket fixedly located in said second oval boreof said ferrule;

a pencil lead guide being of tubelike shape fixedly located in saidfirst small bore of said ferrule,

all above parts in concentric alignment.

2. A mechanical pencil for fine lead having a pushbuttontype leadadvancing mechanism, comprising in combination,

a barrel forming the main portion of said pencil, said barrel saidplunger means from rotating. 3. A mechanical pencil for fine lead havinga pushbuttontype lead advancing mechanism, comprising in combination,

including an interior thread in the front end portion of its a barrelforming the main portion of said pencil, said barrel bore; 5 includingan interior thread in the front end portion of its a tapered ferruleadjoining the front end of said barrel and includingan interior threadin its rear portion and a writa t p d fermie l fl end of 5 ald barn]alld mg tip at its from end; ncludlngan lnterlor thread ln lts rearportion and a writplug for connecting said ferrule to said barrel, saidplug 8 P at Its fi comprising a threaded rear section screwable into the10 3 P 8 said ferrule f said banelf P 8 front end of said barrel, athreaded middle section adcompflsms a threaded rear when screwable a thejacent thereto and screwable into the rear end of said ferf end ofbarrel- 8 ufreaded mlddle e rule, and a front section of a diametersmaller than said jacent thereto and ScrFwable 5 the rear end of sad ieand in ed Sd135$$2$ as plugbems hollow mid having F5 from PPmOP a borelu being hollow and having in its fruit portion a bore Secuon ofenlarged diameter adjomed by an mtenor abuts ecfion of enlar ed diameterad 'oined b an interior abutshoulder; ment shoulder 8 J y hollow plungermeans arranged inside said barrel, reaching through said plug and beinglongitudinally a "l plunger meims arranged m.slde i movable from arearward rest sition into a forward reachmg through sad plug and bemglongnudmauy d b k 1 p0 l l t h movable from a rearward rest positioninto a forward fr p i 5 c P position and back, said plunger meansincluding clutch P 3 a a? sm 1 c meims g means in its front portion,said clutch means being guided e en arse, meter ore Sal p inside saidenlarged diameter bore section of said plug f a by Gus movement 9 gnppmga lead placed and capable, by this movement, of gripping a lead placedInside means when means inside said clutch means when said plunger meansreturns to its rest p i and of releasing said lead when Said to its restposition, and of releaslng said lead when Said plunger means moves toits forw r posi i n; plunger means moves to its forward position;

Sai taper ferru f rth r h ving in i m l Portion a said tapered ferrulefurther having in its middle portion a Central Positioning bore, theWall Of Said bore closely central positioning bore, the wall of saidbore closely fitting over said front section of said plug, so that axialfitting over said front section of said plug, so that axial alignmentbetween said clutch means and said writing tip alignment between saidclutch means and said writing tip is maintained regardless of anymisalignment between is maintained regardless of any mlsallgnmentbetween said ferrule and said barrel; said ferrule and said barrel;

said plunger means further including spring means to urge said plungermeans further including spring means to urge said plunger means into itsrest position, a plunger casing said plunger means into its restposition, a plunger casing attached to and extending rearwardly fromsaid clutch attached to and extending rearwardly from said clutch meansand through a major part of said barrel, and a m n nd through a majorpart Of aid rrel, n a plunger button removably inserted into the rearend of p u g blmon remov ly in r in o t re r nd Of said plunger casingand projecting therefrom and beyond ig p ng i i l gd g p'l jzzz ighlggjrflzggiogf the rear end of said barrel; said plunger casing beingare real en 31 l ranged to hold a supply of leads for successiveinsertion f g 1 a pp y of leads for successlve msemo" into said clutchmeans; c F

said barrel further including an interior thread in the rear Salli p ssg s g -lz l r s P 3 3g end portion of its bore, a hollow end cap havinga P avmg a lame no "8" a 0 ea threaded forward portion screwable intothe rear end of p f 'g f 2 P21" when remgved g l g plmfger said barrel,said end cap including a longitudinal interior casmg' g a P 9 removeacmre ea Secnons groove, and said plunger button including a matchingfrom the mung up ofsald ferrule radial nose slidably retained by saidgroove, to prevent so

1. A mechanical pencil for fine lead having a pushbutton-type leadadvancing mechanism, comprising in combination: An elongated barrelhaving a bore, a front end and rear end; said barrel including aninterior thread in said front end and an outer external diametricalalignment projection on said front end and an upper internal thread andan internal diametrical alignment portion at said rear end; a rear endcap 1, mounted on the rear end of said barrel having a bore, a front endwith an external thread and an external diametrical alignment portion;said external thread and said external alignment portion of said borebeing in diametrical alignment and fitting engagement with said upperinternal thread, and said internal diametrical alignment portion of saidrear end of said barrel; a tubular plunger casing, with an upper end anda lower end, having thin metal walls being a spare pencil lead magazine;a plunger button of cylindrical shape having a necked portionnonrotatingly, slidably and reciprocatingly mounted in said end cap, thesaid upper end of the said plunger casing being removably mounted withits inside diameter upon said necked portion of said plunger button; asleevelike plunger coupling having an internal thread, an externaldiameter, an external circular groove and a necked diametrical part,said lower end of said plunger casing being fixedly mounted upon saidexternal diameter of said plunger coupling pressingly engaging saidcircular groove of said coupling; a ferrule having an outsidecylindrical rear portion and a forward tapered portion, an internaldiametrical fitting portion at said rear portion engaging fittingly saidexternal diametrical fitting portion on said front end of said barrel;said ferrule also having, starting in sequence at its said forwardportion, concentric cylindrical bores, comprising: a first small bore. asecond oval-shaped bore, a third bore, a fourth bore, an abutmentbetween said third and said fourth bore; a fifth bore, and a sixth borebeing an internal thread; a plug rigidly connecting said barrel and saidferrule; said plug having rear and front parts integrally arranged fromits rear to front, said rear part having: a necked projection, a largerexternal thread in fixed engagement with said interior thread in saidfront end of said barrel, a relief diameter, said front part having: asmaller external thread in fixed engagement with said sixth bore beingan internal thread of said ferrule, and a smaller outside diameter atsaid front part of said plug engaged aligningly and fittingly with saidfourth bore of said ferrule, said plug further comprising: a longsmaller bore starting at said rear part of said plug, a conical bore,and a larger bore at its front part, a tubelike plunger, having an upperpart and a lower part, said upper part comprising an external threadfixedly engaged with said internal thread of said plunger coupling andan outside diameter, fittingly and slidingly engaging in said longsmaller bore of said plug, said lower part of said plunger having asmall internal thread at said lower part, and comprising an inner boreof a size permitting passing said pencil lead therethrough; a clutchhead having a front end and rear end being concentric, comprising: along thin neck; an external thread at said rear end fixedly mounted andin engagement with said small internal thread at said lower part of saidplunger; an axial bore for slidingly passing and holding said pencillead; a colletlike clutch portion at said front end of said clutch headfor alternately holding, feeding and clamping said pencil lead, saidclutch head having at least two longitudinal slots in said front endportion and being located in said forward portion of said ferrule,whereby a larger portion of said pencil lead can be used up; a clutchsleeve slidably mounted in said larger bore in said front part of saidplug, said clutch sleeve having an upper smaller bore and a lower largerbore and a conical clutchaffectinG middle portion; a compression springaxially mounted between said plunger coupling and said plug being heldconcentric by said necked diametrical part of said coupling and saidnecked projection of said plug; a pencil lead-supporting gasket fixedlylocated in said second oval bore of said ferrule; a pencil lead guidebeing of tubelike shape fixedly located in said first small bore of saidferrule, all above parts in concentric alignment.
 2. A mechanical pencilfor fine lead having a pushbutton-type lead advancing mechanism,comprising in combination, a barrel forming the main portion of saidpencil, said barrel including an interior thread in the front endportion of its bore; a tapered ferrule adjoining the front end of saidbarrel and including an interior thread in its rear portion and awriting tip at its front end; a plug for connecting said ferrule to saidbarrel, said plug comprising a threaded rear section screwable into thefront end of said barrel, a threaded middle section adjacent thereto andscrewable into the rear end of said ferrule, and a front section of adiameter smaller than said middle section and extending forwardlytherefrom, said plug being hollow and having in its front portion a boresection of enlarged diameter adjoined by an interior abutment shoulder;a hollow plunger means arranged inside said barrel, reaching throughsaid plug and being longitudinally movable from a rearward rest positioninto a forward position and back, said plunger means including clutchmeans in its front portion, said clutch means being guided inside saidenlarged diameter bore section of said plug and capable, by thismovement, of gripping a lead placed inside said clutch means when saidplunger means returns to its rest position, and of releasing said leadwhen said plunger means moves to its forward position; said taperedferrule further having in its middle portion a central positioning bore,the wall of said bore closely fitting over said front section of saidplug, so that axial alignment between said clutch means and said writingtip is maintained regardless of any misalignment between said ferruleand said barrel; said plunger means further including spring means tourge said plunger means into its rest position, a plunger casingattached to and extending rearwardly from said clutch means and througha major part of said barrel, and a plunger button removably insertedinto the rear end of said plunger casing and projecting therefrom andbeyond the rear end of said barrel; said plunger casing being arrangedto hold a supply of leads for successive insertion into said clutchmeans; said barrel further including an interior thread in the rear endportion of its bore, a hollow end cap having a threaded forward portionscrewable into the rear end of said barrel, said end cap including alongitudinal interior groove, and said plunger button including amatching radial nose slidably retained by said groove, to prevent saidplunger means from rotating.
 3. A mechanical pencil for fine lead havinga pushbutton-type lead advancing mechanism, comprising in combination, abarrel forming the main portion of said pencil, said barrel including aninterior thread in the front end portion of its bore; a tapered ferruleadjoining the front end of said barrel and including an interior threadin its rear portion and a writing tip at its front end; a plug forconnecting said ferrule to said barrel, said plug comprising a threadedrear section screwable into the front end of said barrel, a threadedmiddle section adjacent thereto and screwable into the rear end of saidferrule, and a front section of a diameter smaller than said middlesection and extending forwardly therefrom, said plug being hollow andhaving in its front portion a bore section of enlarged diameter adjoinedby an interior abutment shoulder; a hollow plunger means arranged insidesaid barrel, reaching through said plug and being longitudiNally movablefrom a rearward rest position into a forward position and back, saidplunger means including clutch means in its front portion, said clutchmeans being guided inside said enlarged diameter bore section of saidplug and capable, by this movement, of gripping a lead placed insidesaid clutch means when said plunger means returns to its rest position,and of releasing said lead when said plunger means moves to its forwardposition; said tapered ferrule further having in its middle portion acentral positioning bore, the wall of said bore closely fitting oversaid front section of said plug, so that axial alignment between saidclutch means and said writing tip is maintained regardless of anymisalignment between said ferrule and said barrel; said plunger meansfurther including spring means to urge said plunger means into its restposition, a plunger casing attached to and extending rearwardly fromsaid clutch means and through a major part of said barrel, and a plungerbutton removably inserted into the rear end of said plunger casing andprojecting therefrom and beyond the rear end of said barrel; saidplunger casing being arranged to hold a supply of leads for successiveinsertion into said clutch means; said plunger button including aforward-projecting pin, said pin having a diameter not larger than thatof a lead, said plunger button and pin, when removed from said plungercasing, being adapted to remove fractured lead sections from the writingtip of said ferrule.